With image processors, processing for noise reductions, etc. is implemented for the purpose of preventing image deteriorations. As set forth typically in JP(A)2000-69291, smoothing filter size is changed on the basis of the noise characteristics of an image input medium to apply smoothing processing to an image, wherein image deteriorations are prevented and fast operation is achievable.
However, problems with the prior art technique set forth in the aforesaid JP(A)2000-69291 are:
(1) the characteristics of smoothing processing are changed depending on the noise characteristics of the image input medium; the frequency characteristics for transform processing cannot be changed in association with a change in the frequency characteristics of an output medium or post-processor, and (2) smoothing filter size is changed on the basis of the noise characteristics to apply smoothing processing to the image. Therefore, the prior art cannot be compatible with a plurality of filters.
The present invention has been made with such problems with the prior art in mind, and has for its object the provision of an image processor that can provide a solution to the aforesaid problems (1) and (2) so that it can be compatible with a change in the frequency characteristics of a post-processor, and offer a sensible tradeoff between proper noise reductions and holding the details of an image.